MULTICS TECHNICAL BULLETIN                             MTB-689-03

To:       MTB Distribution

From:     Doug Howe

Date:     August 20, 1986

Subject:  The C Runtime System on Multics


This  MTB  describes  the  C   runtime  library  as  it  will  be
implemented on Multics.  It is expected  to be a complete list of
the runtime library available from System V Release 2.0(1)

Changes within this Mtb will be marked with change bars.

Revision 3:                                                       |
Changes  include a complete  list of the  runtime routines to  be |
available with the C compiler.                                    |



(1) Unix and System V Release 2.0 are registered trademarks of AT
    & T

MTB-689-03                                       C Runtime System

Comments should be sent to the authors:

     via Multics mail to:


     via posted mail to:

        Douglas G.  Howe
        Advanced Computing Technology Centre
        Foothills Professional Building
        1620 29th St., N.W.
        Calgary Alberta Canada   T2N-4L7

     via telephone to:

        (403)-284-6432 (Howe)

     via forum on System-M to:

        >udd>m>DGHowe>mtgs_dir>c>c_imp (c)


Multics  project internal documentation;  no to be  reproduced or
distributed ouside the Multics project.

C Runtime System                                       MTB-689-03

                        TABLE OF CONTENTS

Section    Page  Subject
=======    ====  =======

1          1     Preface
2          2     Introduction
2.1        2     . . Goal
2.2        2     . . Background
2.3        2     . . References For this Document
3          3     Name Conflicts
4          3     C Runtime Routines
5          3     Math Routines
5.1        3     . . abs
5.2        3     . . acos
5.3        4     . . asin
5.4        4     . . atan
5.5        4     . . atan2
5.6        4     . . cabs
5.7        4     . . ceil
5.8        5     . . cos
5.9        5     . . cosh
5.10       5     . . exp
5.11       5     . . fabs
5.12       5     . . floor
5.13       5     . . frexp
5.14       6     . . hypot
5.15       6     . . ldexp
5.16       6     . . log
5.17       6     . . log10
5.18       6     . . modf
5.19       6     . . pow
5.20       7     . . sin
5.21       7     . . sinh
5.22       7     . . sqrt
5.23       7     . . tan
5.24       7     . . tanh
6          8     Utility and Conversion Routines
6.1        8     . . atof
6.2        8     . . atoi
6.3        8     . . atol
6.4        8     . . ecvt
6.5        9     . . fcvt
6.6        9     . . gcvt
6.7        9     . . isalpha
6.8        9     . . isalnum
6.9        9     . . isascii
6.10       10    . . iscntrl
6.11       10    . . isdigit
6.12       10    . . islower
6.13       10    . . isprint
6.14       10    . . ispunct

MTB-689-03                                       C Runtime System

6.15       10    . . isspace
6.16       11    . . isupper
6.17       11    . . memccpy
6.18       11    . . memchr
6.19       11    . . memcmp
6.20       11    . . memcpy
6.21       11    . . memset
6.22       12    . . strchr
6.23       12    . . strrchr
6.24       12    . . strcat
6.25       12    . . strcmp
6.26       12    . . strcpy
6.27       13    . . strlen
6.28       13    . . strncat
6.29       13    . . strncmp
6.30       13    . . strncpy
6.31       13    . . toascii
6.32       14    . . tolower
6.33       14    . . toupper
7          15    Storage Routines
7.1        15    . . calloc
7.2        15    . . free
7.3        15    . . malloc
7.4        15    . . realloc
8          16    Input and Output
9          16    General I/O Routines
9.1        16    . . exit
9.2        17    . . _exit
9.3        17    . . unlink
10         18    I/O using File Pointers
10.1       18    . . clearerr
10.2       18    . . fclose
10.3       18    . . fdopen
10.4       19    . . feof
10.5       19    . . ferror
10.6       19    . . fileno
10.7       19    . . fflush
10.8       19    . . fgetc
10.9       19    . . fgets
10.10      20    . . findiop
10.11      20    . . fopen
10.12      20    . . fprintf
10.13      20    . . fputc
10.14      20    . . fputs
10.15      21    . . fread
10.16      21    . . freopen
10.17      21    . . fscanf
10.18      21    . . fseek
10.19      21    . . ftell
10.20      22    . . fwrite
10.21      22    . . getc
10.22      22    . . getchar

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10.23      22    . . gets
10.24      22    . . getw
10.25      22    . . printf
10.26      22    . . putc
10.27      23    . . putchar
10.28      23    . . puts
10.29      23    . . putw
10.30      23    . . rewind
10.31      23    . . scanf
10.32      23    . . setbuf
10.33      24    . . setvbuf
10.34      24    . . sprintf
10.35      24    . . sscanf
10.36      24    . . ungetc
11         25    I/O using File Descriptor Numbers
11.1       25    . . close
11.2       25    . . creat
11.3       25    . . lseek
11.4       25    . . open
11.5       26    . . read
11.6       26    . . write
12         26    Miscellaneous Routines
12.1       26    . . ctime
12.2       26    . . fork
12.3       27    . . longjmp
12.4       27    . . mktemp
12.5       27    . . sbrk
12.6       27    . . setjmp
12.7       28    . . system
12.8       28    . . tempnam
12.9       28    . . tmpfile
12.10      28    . . tmpnam
12.11      28    . . time

C Runtime System                                       MTB-689-03

1.  Preface

This MTB describes the Runtime  Library that will support the 'C'
language on Multics.                                              *

MTB-689-03                                       C Runtime System

2.  Introduction

2.1.  Goal

The Goal of this MTB is to describe a C runtime System compatible
with  System V  release 2.0;  that will  allow the  porting of  C
programs and packages from other systems.

2.2.  Background

The  C language  was designed  to be  portable, and  is currently
working  on many different  machines and operating  systems.  C's
native  environment is  usually  a  Unix operating  system, which
contains  both  C  librarys   and  system  libraries.   A  common
misconception is that C consists of both of these libraries, when
they are actually seperate:  one for the language support and the
other for the system support.   The Runtime Library to be defined
here  will only  contain those  routines that  the C  language is
dependant  on and  will leave   the development  of an  operating
system library to a later date.

2.3.  References For this Document

1) MTB-647 created by Greg Baryza.

2) The C Programming Language
   Brian W.  Kernighan & Dennis M.  Ritchie
   Prentice-Hall (1978)
   Englewood Cliffs, New Jersey

3) The Multics Programmers Reference Manual (10.2 AG91-03A)

4) MTB on C for Multics by Doug Howe (MTB 688).

5) MTB  titled The Multics  C Execution Environment  by Doug Howe
(MTB 691).

C Runtime System                                       MTB-689-03

3.  Name Conflicts

Several C routines listed below,  have name clashes with existing
Multics routines.  These  clashes will be taken care  of with the
use of the existing binder or with the new Link Editor defined in
Mtb 718.

ceil   date   exit   floor   mod   system   time   unlink

4.  C Runtime Routines

The  C   runtime  routines  have  been  broken   down  into  five
categories:   Math  Routines,   Utility  &  Conversion  Routines,
Storage   Routines,  Input/Output  Routines,   and  Miscellaneous

5.  Math Routines

The  math routines  being implemented  will use  the Mutlics math |
routines  whenever possible.   The following  list defines  the C |
Math Routines:

abs          cabs          fabs        log        sin
acos         ceil          floor       log10      sinh
asin         cos           frexp       modf       sqrt
atan         cosh          hypot       pow        tan
atan2        exp           ldexp       rpow       tanh

5.1.  abs

int abs(i);
int i;
Returns the absolute value of its argument.

MTB-689-03                                       C Runtime System

5.2.  acos

double acos(x);
double x;
Returns the arc-cosine of its argument in radians.

5.3.  asin

double asin(x);
double x;
Returns the arc-sine of its argument in radians.

5.4.  atan

double atan(x);
double x;
Returns the arc-tangent of its argument in radians.

5.5.  atan2

double atan2(x,y);
double x,y;
Returns the arc-tangent of x/y in the range of -pi to pi.

5.6.  cabs

double cabs(z);
struct { double x,y; } z;
Returns the  absolute value of  a complex number.   Equivalent to
sqrt(x^2 + y^2).

5.7.  ceil

double ceil(x);
double x;
Returns its argument rounded up if modf (x, temp) > 0.

C Runtime System                                       MTB-689-03

5.8.  cos

double cos(x);
double x;
Returns the cosine of its argument.  (radians).

5.9.  cosh

double cosh(x);
double x;
Returns the hyperbolic-cosine of its argument.

5.10.  exp

double exp(x);
double x;
Returns the e to the power of its argument.  (anti-log base e)

5.11.  fabs

double fabs(x);
double x;
Returns the absolute value of its argument.

5.12.  floor

double floor(x);
double x;
Returns its argument rounded down if modf (x, temp) < 0.

5.13.  frexp

double frexp(value,eptr);
double value;
int *eptr;
Returns the mantissa of a double  value x, of magnitude less than
1 and stores  an integer n such that value =  x * 2**n indirectly
through eptr;

MTB-689-03                                       C Runtime System

5.14.  hypot

double hypot(x,y);
double x,y;
Returns the hypotenuse length given two co-ordinates.  Equivalent
to sqrt(x^2 + y^2).

5.15.  ldexp

double ldexp (value,exp);
double value;
int exp;
Returns the value of value * 2**exp;

5.16.  log

double log(x);
double x;
Returns the log base e of its argument.

5.17.  log10

double log10(x);
double x;
Returns the log base 10 of its argument.

5.18.  modf

double modf(value,iptr);
double  value,*iptr;
Returns the fractional part of  value and stores the integer part
indirectly through iptr.

5.19.  pow

double pow(x,y);
double x,y;
Returns  the first  argument raised  to the  power of  the second

C Runtime System                                       MTB-689-03

5.20.  sin

double sin(x);
double x;
Returns the sine of its argument.  (radians).

5.21.  sinh

double sinh(x);
double x;
Returns the hyperbolic-sine of its argument.

5.22.  sqrt

double sqrt(x);
double x;
Returns the square-root of its argument.

5.23.  tan

double tan(x);
double x;
Returns the tangent of its argument.  (radians).

5.24.  tanh

double tanh(x);
double x;
Returns the hyperbolic-tangent of its argument.

MTB-689-03                                       C Runtime System

6.  Utility and Conversion Routines

The following routines are considered to be Utility or conversion

atof      isalnum      isspace    strchr       strncmp            |
atoi      isascii      isupper    strrchr      strncpy            |
atol      iscntrl      memccpy    strcat       toascii            |
ecvt      isdigit      memchr     strcmp       tolower            |
fcvt      islower      memcmp     strcpy       toupper            |
gcvt      isprint      memcpy     strlen                          |
isalpha   ispunct      memset     strncat                         |

6.1.  atof

double atof(x);
char *x;
Ascii to float.  Convert a string to a double value.

6.2.  atoi

int atoi(x);
char *x;
Ascii to integer.  Convert a string to a integer value.

6.3.  atol

long atol(x);
char *x;
Ascii to long.  Convert a string to a long value.

6.4.  ecvt

char * ecvt(value,ndigit,decpt,sign);
double value;
int ndigit,*decpt,*sign;
Converts 'value' into a character string.

C Runtime System                                       MTB-689-03

6.5.  fcvt

char * fcvt(value,ndigit,decpt,sign);
double value;
int ndigit,*decpt,*sign;
Convert  'value'  to  ascii  string  rounded  as  in Fortrans 'F'

6.6.  gcvt

char * gcvt(value,ndigit,buffer);
double value;
int ndigit;
char *buffer;
Convert 'value' into a string allocated in 'buffer' with 'ndigit'
significant  digits.   Uses  Fortrans   'F'  format  if  possible
otherwise 'E' format.

6.7.  isalpha

isalpha (c);

Is a MACRO defined with  the #define statement.  Returns non-zero
if 'c' is alphabetic, zero if not.

6.8.  isalnum

isalnum (c);

Is a MACRO defined with  the #define statement.  Returns non-zero
if c is numeric, zero if not.

6.9.  isascii

isascii (c);

Is a MACRO defined with  the #define statement.  Returns non-zero
if c is an Ascii character, zero if not.

6.10.  iscntrl

iscntrl (c);

MTB-689-03                                       C Runtime System

Is a MACRO defined with  the #define statement.  Returns non-zero
if c is a control character (delete char (177) or less than 040),
zero if not.

6.11.  isdigit

isdigit (c);

Is a MACRO defined with  the #define statement.  Returns non-zero
if 'c' is digit, zero if not.

6.12.  islower

islower (c);

Is a MACRO defined with  the #define statement.  Returns non-zero
if 'c' is lower-case letter, zero if not.

6.13.  isprint

isprint (c);

Is a MACRO defined with  the #define statement.  Returns non-zero
if c is a printable character (040 through 176), zero if not.

6.14.  ispunct

ispunct  (c); Is  a MACRO   defined with  the #define  statement.
Returns non-zero if c is a punctuation character, zero if not.

6.15.  isspace

isspace (c);

Is a MACRO defined with  the #define statement.  Returns non-zero
if 'c' is blank, tab or newline; zero if not.

6.16.  isupper

isupper (c);

C Runtime System                                       MTB-689-03

Is a MACRO defined with  the #define statement.  Returns non-zero
if 'c' is upper-case letter, zero if not.

6.17.  memccpy                                                    |
char *memccpy (s1, s2, c, n)                                      |
char *s1, *s2;                                                    |
int  c, n;                                                        |
Copy characters from s2 to s1, stopping after the first occurence |
of the character c, or after n characters have been copied.       |
6.18.  memchr                                                     |
char *memchr (s, c, n)                                            |
char *s;                                                          |
int  c, n;                                                        |
Returna  pointer to  the first  occurence  of  c in  the first  n |
characters of s or null if c does not exist.                      |
6.19.  memcmp                                                     |
int memcmp (s1, s2, n)                                            |
char *s1, *s2;                                                    |
int  n;                                                           |
Compares the first  n characters of s1 to s2 and  returns < 0 (if |
s1 is < s2) or 0 (if s1 = s2) or > 0 (if s1 > s2).                |
6.20.  memcpy                                                     |
char *memcpy (s1, s2, n)                                          |
char *s1, *s2;                                                    |
int  n;                                                           |
Copy n characters from s2 to s1 returning s1.                     |
6.21.  memset                                                     |
char *memset (s, c, n)                                            |
char *s;                                                          |
int  c, n;                                                        |
Set the first n characters in s to c returning s.                 |

MTB-689-03                                       C Runtime System

6.22.  strchr

char *strchr(s,c);
char *s,c;
Returns a pointer to the first occurance  of c in the string s or
null if  c does not occur  in string s.  strchr  is equivalent to
index in some verisons of C.

6.23.  strrchr

char *strrchr(s,c);
char *s,c;
Returns a pointer  to the last occurance of c in  the string s or
null if c  does not occur in string s.   strrchr is equivalent to
rindex in some versions of C.

6.24.  strcat

char * strcat(x,y);
char *x,*y;
Append y to x returning a pointer to the result.

6.25.  strcmp

int strcmp(x,y);
char *x,*y;
Lexigraphically compare  x and y returning an  integer value that
describes their relationship.
     x < y  returns -1
     x = y  returns 0
     x > y  returns 1

6.26.  strcpy

char * strcpy(x,y);
char *x,*y;
Copy y into x returning the result.

C Runtime System                                       MTB-689-03

6.27.  strlen

int strlen(x);
char *x;
Return the length of the string.

6.28.  strncat

char * strncat(x,y,n);
char *x,*y;
int  n;
Append at most n characters from y into x returning the result.

6.29.  strncmp

int strncmp(x,y,n);
char *x,*y;
int  n;
Lexigraphically  compare at  most n  characters between  x and  y
returning an integer value that describes their relationship.

     x < y returns -1
     x = y returns 0
     x > y returns 1

6.30.  strncpy

char * strncpy(x,y,n);
char *x,*y;
int  n;
Copies at most n characters from y into x returning the result.   |
6.31.  toascii                                                    |
int toascii (c)                                                   |
int c;                                                            |
Converts the inputed integer to an ascii character.               |
6.32.  tolower                                                    |
int tolower (c)                                                   |
int c;                                                            |
Converts the inputed character to its lower case equivalent.      |

MTB-689-03                                       C Runtime System

6.33.  toupper                                                    |
int tolower (c)                                                   |
int c;                                                            |
Converts the inputed character to its upper case equivalent.      |

C Runtime System                                       MTB-689-03

7.  Storage Routines

The standard Unix storage routines of malloc, calloc, realloc and
free will  be implemented for Multics using  the standard Multics
area manager.  This will limit  the maximum size of an allocation
to  255K words -  50 words for  the area managers  overhead.  The
Storage Routines are outlined below:

calloc   free   malloc   realloc

7.1.  calloc

char * calloc();
string = calloc(integer_x, integer_y);
Return a pointer to enough clear  space (zeroed) to hold x copies
of size y.  The storage is later freed via a call to 'free'.

7.2.  free

void free();
Free  the space  previously allocated  at ptr.   The storage must
have  been  allocated  via  the  'calloc',  'malloc' or 'realloc'

7.3.  malloc

char * malloc();
string = malloc(size);
Returns a  pointer to allocated  space sufficient to  hold 'size'
bytes.  The storage is later freed via a call to 'free'.

7.4.  realloc

char * realloc();
string = realloc(oldloc, size);
Re-allocate storage  returning a pointer to 'size'  bytes given a
previously  allocated  pointer  'oldloc'.   `oldloc'  must  be  a
pointer  to a non-freed  area of storage.   If `oldloc' has  been
freed prior to the call to realloc the results are unpredictable.
The storage is later freed via 'free'.

MTB-689-03                                       C Runtime System

NOTE:   The above  is a  redefinition of  the original  C routine
'realloc'.   The original  routine reallocated  storage that  had
just been freed.

8.  Input and Output

In C, some routines refer to  files that are indicated by integer
values (file descriptor numbers) and some routines refer to files
that are  indicated by pointers (file pointer  or file descriptor

Unix, at it's basic level references files via a file descriptor.
There  is a  maximum number  of these  descriptors available  per
process (20).  Multics on the other hand uses a defined structure
called the iocb block to allow references to segments.

The FILE pointer type of C is a pointer to a defined structure of
type FILE  which contains the  files descriptor number  and other
associated information.  The routines  that perform file I/O with
FILE pointers call a series of  base level routines with the file
descriptor from the structure that they point to.

Therefore Multics C will redefine  the iobuf structure to include
a pointer to an iocb block so that the IO routines can access the
standard Multics iocb block structure.                            *

9.  General I/O Routines

The following is a list of general I/O Routines.                  *

exit  _exit  unlink

9.1.  exit

void exit(code);
int code;
Leave  main  procedure  and  close   all  files  opened  in  main
procedure.  Set  C_exit_status_severity_ to 'code'.   `exit' will
signal a  condition to be trapped  in main_ which will  reset the
current environment and return the  passed status code unless the
current level  of exectuion is 0.   See the MTB on  the Execution
Environment (MTB 691) for details.

C Runtime System                                       MTB-689-03

9.2.  _exit

void _exit(code);
int code;
Same as exit  except no files are closed.   Leave main procedure,
setting  status variable  to 'code'.   Due to  the environment of
Multics and  the structure of  the C environment  on Multics this
routine will generate an error message.

9.3.  unlink

int unlink(filename);
char *filename;
Delete file 'filename'.  Returns  a zero if successful.  Although
this  is a  Unix system  function it  will be  required by  the C
language.   This will  operate similar  to the  delete command on

MTB-689-03                                       C Runtime System

10.  I/O using File Pointers

These routines  do I/O on  files indicated by  file pointers.  By
convention their are three special file pointers:  stdin, stdout,
and  stderr.   (corresponding  to  user_input,  user_output,  and

The following routines expect file pointers as their arguments or
return file pointers as their output.

clearerr      fopen       getc            scanf                   |
fclose        fprintf     gets            setbuf                  |
fdopen        fputc       getw            setvbuf                 |
feof          fputs       getchar         sprintf                 |
ferror        fread       printf          sscanf                  |
feof          fscanf      putc            ungetc                  |
fflush        freopen     putchar                                 |
fgetc         fseek       puts                                    |
fgets         ftell       putw                                    |
findiop       fwrite      rewind                                  |

10.1.  clearerr

clearerr(fp); FILE *fp;

Is a MACRO defined with  the #define statement.  Clears the error
flag associated with the file pointed to by fp.

10.2.  fclose

int fclose(fp);
FILE  *fp;
Close the file pointed to by fp.

10.3.  fdopen

FILE *fdopen (fd,type);
int  fd;
char *type;
Associates a stream with a file descriptor.  Where stream implies
buffered IO.

C Runtime System                                       MTB-689-03

10.4.  feof

int feof(fp); FILE *fp;

Returns  non-zero  when  end-of-file  is  reached  on  input file
pointed to by fp.

10.5.  ferror

int ferror(fp);
FILE  *fp;
Returns non-zero after an error occurs while reading/writing file
pointed to by fp.  The error indication lasts until a clearerr is

10.6.  fileno

fileno (fp); FILE *fp;

Is a MACRO defined with  the #define statement.  Returns the file
descriptor associated with the file pointer.

10.7.  fflush

int  fflush(fp);
FILE  *fp;
Flush out any pending output on file pointed to by fp.

10.8.  fgetc

int fgetc(fp);
FILE  *fp;
Return a character/int from file pointed to by fp.

10.9.  fgets

char *fgets(line,MAXLINE,fp);
char  *line;
int   MAXLINE;
FILE  *fp;
Returns line.   Read at most MAXLINE-1 characters  into line from
file pointed to by fp.

MTB-689-03                                       C Runtime System

10.10.  findiop                                                   |
FILE *findiop ()                                                  |
Returns a FILE pointer to the next free iobuf entry.              |

10.11.  fopen

FILE *fopen(filename,mode);
char  *filename,*mode;
Open a file named filename with modes mode returning a pointer to

10.12.  fprintf

int fprintf(fp,control_string);
FILE  *fp;
char  *control_string;
Output  arguments under the  control of "control_string"  to file
pointed to by fp.

10.13.  fputc

int fputc(c,fp);
FILE  *fp;
char  c;
Output character 'c' into file pointed to by fp.

10.14.  fputs

int fputs(string,fp);
FILE  *fp;
char  *string;
Output string to file pointed to by fp.

10.15.  fread

int fread(buffer,size,n,fp);
FILE  *fp;
char  *buffer;
int   size,n;
Read into buffer at most n items of size 'size' from file pointed
to by fp.  Return the number of items actually read.

C Runtime System                                       MTB-689-03

10.16.  freopen

FILE *freopen(filename,type,fp);
char  *filename,*type;
FILE  *fp;
Returns  original value  of fp.   Closes file  pointed to  by fp.
Opens  file "filename" with  mode "type" and  set fp to  point to
this file.

10.17.  fscanf

int fscanf(fp,control_string);
FILE  *fp;
char  *control_string;
Read from file pointed to by fp under control of "control_string"
into  variables  located  by   the  pointer  arguments  following
"control_string".  Returns the number of items successfully read.

10.18.  fseek

int fseek(fp,long_pos,origin);
FILE  *fp;
long  long_pos;
int   origin;
Seeks to a new position in file pointed to by fp.  Change current
file position by long_pos  characters.  When origin=0 relative to
file  start,  origin=1  relative  to  current  position, origin=2
relative to end-of-file.  Returns a zero value when successful.

10.19.  ftell

long ftell(fp);
FILE  *fp;
Obsolete.  Returns the current position  in bytes of file pointed
to by fp.

10.20.  fwrite

int fwrite(buffer,size,n,fp);
FILE  *fp;
char  *buffer;
int   size,n;
Output at most  n items of size 'size' from  buffer into the file
pointed to by fp.

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10.21.  getc

int getc(fp);
FILE  *fp;
Returns  the character/integer value  of the next  character read
from file pointed to by fp.

10.22.  getchar

int getchar();
Returns  the character/integer value  of the next  character read
from standard input.

10.23.  gets

char * gets(string);
char  *string;
Read  a line  from standard  input into  string.  Returns string.
Replaces newline character with null-character (end-of-string).

10.24.  getw

int getw(fp);
FILE *fp;
Gets the next word from the file.

10.25.  printf

int printf(control_string);
char  *control_string
Output  arguments to  standard output  using format  specified in

10.26.  putc

int putc(c,fp);
FILE  *fp;
char  c;
Output a character 'c' into file  pointed to by 'fp'.  Return the

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10.27.  putchar

int putchar(c);
char  c;
Output a character 'c' to standard output.  Return the character.

10.28.  puts

int puts(string);
char  *string;
Output a string and a newline char to stdio.

10.29.  putw

FILE *fp;
Putw writes the word w to the file fp;

10.30.  rewind

void rewind(fp);
FILE *fp
Resets the  file pointed to  by fp to  the begining of  the file.
Reset  any error  flags set  for the  file and  flush the  buffer
associated with the file.

10.31.  scanf

int scanf(string);
char  *string;
Reads  from standard  input assigning  to pointer  variable using
format  specified  by  "control_string".   Return  the  number of
values successfully read.

10.32.  setbuf

FILE  *fp;
char  *buf;
Use  buf as the  I/O buffer used  by the file  pointed to by  fp.
Note:   buf must  be at  least as  long as  the manifest constant

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10.33.  setvbuf                                                   |
int setvbuf (fp, buf, type, size)                                 |
FILE *fp;                                                         |
char *buf;                                                        |
int  type, size;                                                  |
Use buf as the I/O buffer for the file pointed to by fp.  Set the |
file buffer type to one of the following:                         |
     IOFBF causes input/ouput to be fully buffered.               |
     IOLBF  causes input/output to  be line buffered;  the buffer |
     will  be flushed  when a  new line  is written  or when  the |
     buffer is full, or if input is requested.                    |
     IONBF causes input/output to be unbuffered.                  |

10.34.  sprintf

char *sprintf(string,control_string);
char  *string,*control_string
Format arguments under control of 'control_string' into string.

NOTE:  Due  to the size difference between  pointers and integers
this function will  return a character pointer and not  an int as
is deifned in some documentation.

10.35.  sscanf

int sscanf(string,control_string);
char  *string,*control_string
Read   values  from   string  using   the  format   specified  in
"control_string"  into  the  arguments  specified  by the pointer
arguments.  Return the number of values successfully read.

10.36.  ungetc

char ungetc(c,fp);
int  c;
FILE  *fp;
Sets c to be the next character read from file pointed to by fp.

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11.  I/O using File Descriptor Numbers

The following routines  perform file I/O on files  indicated by a
file descriptor number (int).  By convention file descriptors map
onto file pointers (0 => stdin, 1 => stdout, 2 => stderr).

close    creat    lseek    open    read    write

11.1.  close

int close(fd);
int  fd;
Close the file indicated by fd.  Return zero if successful.

11.2.  creat

int creat(filename);
char  *filename;
Create  a file  "filename" and  return a  file descriptor  to it.
Although considered a part of  the operating system this function
is required for C program to create a new file.

NOTE:  This is different than  the standard definition but is how
the routine has been implemented in System V.

11.3.  lseek

int lseek(fd,offset,origin);
int  fd,origin;
long offset;
Seek to position 'offset' in  file fd.  When origin=0 position is
relative  to  beginning  of  file.   When  origin=1  position  is
relative to current position.  When origin=2 position is relative
to end-of-file.

11.4.  open

int open(filename,mode);
char  *filename;
int   mode;
Return a  file descriptor indicating file  "filename" opened with
mode "mode".  mode(0,1,2) = (read, write, read_write).

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11.5.  read

int read(fd,buffer,size);
int  fd,size;
char *buffer;
Read  up to size  characters into buffer  from file indicated  by
'fd' returning the actual number of characters read.

11.6.  write

int write(fd,buffer,size);
int  fd,size;
char *buffer;
Write at most 'size' bytes from buffer into file indicated by fd.
Returns the  number of characters actually  written, -1 indicates
an error.

12.  Miscellaneous Routines

The  following miscellaneous  routines will   be added  to the  C
Runtime Library.

ctime     longjmp      sbrk     system      tempnam   time        |
fork      mktemp       setjmp   tmpfile     tmpnam                |

12.1.  ctime

char *ctime(tvec);
int tvec[2];
Ctime  converts a  time as   returned by  the C  runtime function
`time' into  a character string  representing that date  and time
and returns a pointer to it.  The string has the form of "Sun Sep
16 01:03:52 1978n0" where all the fields have a constant width.

12.2.  fork

Fork  is  a  function  on  Unix  Systems  that  generates a child
process.  On Multics  this routine will generate an  error at all

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12.3.  longjmp

jmp_buf env;
int val;
On Multics longjmp will perform a non-local goto to a label saved
in  setjmp.  For  a complete  description see  the definition  of
setjmp that follows.

12.4.  mktemp                                                     |
char *mktemp(template)                                            |
char *template;                                                   |
Mktemp replaces the  string pointed to by template  with a unique |
name.  For Multics this will be  a shriek name.  The minimum size |
required is  15 characters.  For a  more descriptive explaination |
see unique_chars_ in the AG93 Manual.                             |

12.5.  sbrk

char *sbrk(size);
int size;
Sbrk usually is used by C programmers to gain free space in their
heap area.  Sbrk extends the area  by the passed size and returns
a pointer to  the beginning of this allocated  space.  On Multics
this can be achieved by a  call to malloc and therefore sbrk will
return the value of a call to malloc with the parameter size.

12.6.  setjmp

jump_buf env;
Non-local gotos in C are performed by a coordinated use of setjmp
and longjmp.  Setjmp saves the  current Program Counter and Stack
Pointer for refrence in longjmp  which restores the saved values.
On Multics this will be done by saving a label value in setjmp of
the  current location  and performing  a non-local  goto to  that
label  in longjmp.   In this  way the  standard Multics non-local
goto mechanism will be invoked.

12.7.  system

int system(string);
char  *string;
Execute command string returning a standard status code.          |

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12.8.  tempnam                                                    |
char *tempanm (dir, pfx)                                          |
char *dir, *pfx;                                                  |
Tempnam generates a unique file name.  Tempnam allows the user to |
specify what directory  is to be used.  If dir  is null the users |
process directory  will be used.  If  pfx is non null  it will be |
taken to be the prefix of the unique name generated.  If an error |
occurs null will be returned.                                     |
12.9.  tmpfile                                                    |
FILE *tmpfile()                                                   |
Tmpfile creates  a temporary file  opened for update  ("w+").  If |
the file can not be opened  a null is returned otherwise the file |
pointer  is returned.  The  file will be  created in the  process |
directory on Multics.                                             |
12.10.  tmpnam                                                    |
char *tmpnam (s)                                                  |
char *s;                                                          |
tmpnam  will  generate  a  file  name  using  the  users  process |
directory as  a prefix.  The name  will be store on  the heap and |
any further invocations of tmpnam  will destroy the stored value. |
The address  of the stored  name will be  returned.  If s  is non |
null the  name will be store  in s.  s should  be large enough to |
store a full Multics path name (64 characters).                   |

12.11.  time

long time(tloc);
long *tloc;
Time  returns  the  number  of  seconds  that  have elapsed since
00:00:00 01  Jan 1970 GMT.   If tloc is  not null a  copy is also
stored at *tloc.