11-28-2007
Quote:
Originally Posted by
porter
Huge difference, the "|" requires another fork(), possibly the single most expensive call in UNIXdom.
Now that's really useful to know (up till now I hadn't thought about the fact that the shell would have to fork the command) - as people have said, it's not exactly the tool of choice if it has to run fast but I prefer to be pedantic about wasted cycles when I have the luxury of time
Cheers for the pointer!
Last edited by Smiling Dragon; 11-28-2007 at 10:28 PM..
Reason: Speeling
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LEARN ABOUT FREEBSD
system
SYSTEM(3) BSD Library Functions Manual SYSTEM(3)
NAME
system -- pass a command to the shell
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
int
system(const char *string);
DESCRIPTION
The system() function hands the argument string to the command interpreter sh(1). The calling process waits for the shell to finish execut-
ing the command, ignoring SIGINT and SIGQUIT, and blocking SIGCHLD.
If string is a NULL pointer, system() will return non-zero if the command interpreter sh(1) is available, and zero if it is not.
RETURN VALUES
The system() function returns the exit status of the shell as returned by waitpid(2), or -1 if an error occurred when invoking fork(2) or
waitpid(2). A return value of 127 means the execution of the shell failed.
SEE ALSO
sh(1), execve(2), fork(2), waitpid(2), popen(3)
STANDARDS
The system() function conforms to ISO/IEC 9899:1990 (``ISO C90'') and is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.
BSD
June 4, 1993 BSD