sy

Algorithms for Image Processing and Computer Vision Source Code

@c ----------------------------------------------------------------------
@node sync, unix
@heading @code{sync}

@subheading Description

This function is provided only to assist in porting from Unix.  It
always returns an error condition. 

@c ----------------------------------------------------------------------
@node sys_errlist, stdio
@heading @code{sys_errlist}
@subheading Syntax

@example
#include <errno.h>

extern char *sys_errlist[];
@end example

@subheading Description

This array contains error messages, indexed by @code{errno}, that
describe the errors. 

@subheading Example

@example
printf("Error: %s\n", sys_errlist[errno]);
@end example

@c ----------------------------------------------------------------------
@node sys_nerr, stdio
@heading @code{sys_nerr}
@subheading Syntax

@example
#include <errno.h>

extern int sys_nerr;
@end example

@subheading Description

This variable gives the number of error messages in @code{sys_errlist}
(@pxref{sys_errlist}). 

@subheading Example

@example
if (errno < sys_nerr)
  printf("Error: %s\n", sys_errlist[errno]);
@end example

@c ----------------------------------------------------------------------
@node sysconf, posix
@heading @code{sysconf}
@subheading Syntax

@example
#include <unistd.h>

long sysconf(int which);
@end example

@subheading Description

This function returns various system configuration values, based on
@var{which}:

@example
case _SC_ARG_MAX:           return ARG_MAX;
case _SC_CHILD_MAX:         return CHILD_MAX;
case _SC_CLK_TCK:           return CLK_TCK;
case _SC_NGROUPS_MAX:       return NGROUPS_MAX;
case _SC_OPEN_MAX:          return OPEN_MAX;
case _SC_JOB_CONTROL:       return -1;
case _SC_SAVED_IDS:         return -1;
case _SC_VERSION:           return _POSIX_VERSION;
case _SC_XOPEN_VERSION:     return _XOPEN_VERSION;
case _SC_PASS_MAX:          return PASS_MAX;
case _SC_STREAM_MAX:        return _POSIX_STREAM_MAX;
case _SC_TZNAME_MAX:        return TZNAME_MAX;
case _SC_BC_BASE_MAX:       return BC_BASE_MAX;
case _SC_BC_DIM_MAX:        return BC_DIM_MAX;
case _SC_BC_SCALE_MAX:      return BC_SCALE_MAX;
case _SC_COLL_ELEM_MAX:     return COLL_ELEM_MAX;
case _SC_EXPR_NEST_MAX:     return EXPR_NEST_MAX;
case _SC_LINE_MAX:          return LINE_MAX;
case _SC_PASTE_FILES_MAX:   return PASTE_FILES_MAX;
case _SC_RE_DUP_MAX:        return RE_DUP_MAX;
case _SC_SED_PATTERN_MAX:   return SED_PATTERN_MAX;
case _SC_SENDTO_MAX:        return SENDTO_MAX;
case _SC_SORT_LINE_MAX:     return SORT_LINE_MAX;
case _SC_2_VERSION:         return _POSIX2_VERSION;
case _SC_2_C_BIND:          return _POSIX2_C_BIND;
case _SC_2_C_DEV:           return _POSIX2_C_DEV;
case _SC_2_FORT_DEV:        return _POSIX2_FORT_DEV;
case _SC_2_SW_DEV:          return _POSIX2_SW_DEV;
case _SC_CLOCKS_PER_SEC:    return CLOCKS_PER_SEC;
case _SC_AES_OS_VERSION:    return -1;
case _SC_PAGE_SIZE:         return 4096;
case _SC_ATEXIT_MAX:        return ATEXIT_MAX;
@end example

@subheading Return Value

The value.

@c ----------------------------------------------------------------------
@node system, process
@heading @code{system}
@subheading Syntax

@example
#include <stdlib.h>

int system(const char *cmd);
@end example

@subheading Description

This function runs the specified command.

Go32 automatically detects if redirection is requested and will attempt
to run the program directly if not, to work around the fact that
command.com does not return the exit code of the child process.  If it
can't run it directly, command.com is used to run the child. 

@subheading Return Value

The return value of the child process, unless command.com doesn't return
it. 

@subheading Example

@example
system("cc1plus.exe @@cc123456.gp");
@end example