Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: alternatives of exec() system function
Top Forums Programming alternatives of exec() system function Post 302155100 by Raj Kumar Arora on Thursday 3rd of January 2008 01:20:02 AM
Old 01-03-2008
Quote:
Originally Posted by porter
fork and exec are two of the most fundamental calls on a UNIX system, if these are failing the system won't work.

Any alternative, such as "system()" or "popen()" will call fork()/vfork() and exec(), there is not really any other portable way to start a new process and launch a new program in it.

I suggest the errors are in the usage or understanding of what these calls do.

Admittedly, Linux has clone() but that's another story.
Thanks porter for your reply. The problem is not exactly in usage because it is running at few machines too. It may be some sort of environment or previledges problem. Actually now the situation is that I am trying to do that using Multithreading. I am creating two threads.

I needed to call an executable with some arguments in the function body for second thread. For that I am using system() call.

The problem is that :-
1. system() function call is not allowing any further arguments to executable being called as execl() would if I was using a fork()-execl() pair in case of Multiprocessing.

2. I need alternative to system() because system is also creating a new process. And I dont want to create a new process in a thread.

Regards,
Raj Kumar Arora
 

10 More Discussions You Might Find Interesting

1. Programming

exec() system call

hi there, i was reading about the exec() function. and if i m not wrong, exec() kills your present process and starts a new process in its place. the process id remains the same. then it says if exec is successful the text data and stack are overlayed by new file! - i dont get this part "only... (2 Replies)
Discussion started by: a25khan
2 Replies

2. UNIX for Advanced & Expert Users

Alternatives to set the system date ??

Hi all, I need to syncronize a Solaris client with a QNX Server, modifying the client date, I need any alternative to set the sistem date (client Solaris) but i can't use commands date -a XXX (XXX are the time in seconds) and can't use rdate and ntp. How can I do It? :confused: (2 Replies)
Discussion started by: ulisses0205
2 Replies

3. Shell Programming and Scripting

How can I execute own ksh function in find -exec

Hi, I wrote a smiple ksh function send_notification() { ... } and want to execute it on each file, matched by the find command. I tried: find / -name "*.err" -mtime -8 -exec send_notification {} \; but it doesn't work. What should I do? I work in ksh on Hp-Ux. Regards, Pit (11 Replies)
Discussion started by: piooooter
11 Replies

4. UNIX for Advanced & Expert Users

exec to call specific function in C prog

I would like to call a particular function in a C program using execl(). Is this possible using execl or anyother function ? Thanks (2 Replies)
Discussion started by: vpraveen84
2 Replies

5. Programming

Runtime.getSystem.exec() function waits for child

Runtime.getSystem.exec() waits for child process to complete .. I do not want to wait for the child process to complete ..what is the option which has to be used ? (2 Replies)
Discussion started by: shafi2all
2 Replies

6. Shell Programming and Scripting

How to execute piped command using exec or system

Hi All, I want to execute a piped command like 'ls /opt | grep xml' using array as parameters list. How can I do that? (2 Replies)
Discussion started by: bharadiaam
2 Replies

7. Shell Programming and Scripting

Perl variables in exec or system

I am new in Perl. I am working in simple script and the varibles are working well outside the exec or system command. but they don't work as parameters to exec or system command. The script is attached. please help. (8 Replies)
Discussion started by: ahmed_zaher
8 Replies

8. UNIX for Dummies Questions & Answers

Using system function in C

Hi Guys , I want to use system function in C to do the following work. cp <file1> <file2> and then ><file1> e,g cp \var\log\cpm_cpmd_1.log.1 \var\log\cpm_cpmd_1.log.2 and then >\var\log\cpm_cpmd_1.log.1 1. g_config_info.cpmm_config.cpm_log_path=\var\log\ 2. ... (3 Replies)
Discussion started by: meet123321
3 Replies

9. Programming

[C] exec system call

Hi again ;) Now I want to make a program that will execute the programs with exec, asking the user if he wants the program to run in background or foreground. scanf("%c",&caracter); if (caracter=='y'){ printf("Has decidido ejecutarlo en background\n"); if((pid=fork())==0) {// fork para... (3 Replies)
Discussion started by: lamachejo
3 Replies

10. Shell Programming and Scripting

Script Variables Inquiry, Values Okay in Standalone Exec, No-Show in Cron Exec

I have the following bash script lines in a file named test.sh. #!/bin/bash # # Write Date to cron.log # echo "Begin SSI Load $(date +%d%b%y_%T)" # # Get the latest rates file for processing. # d=$(ls -tr /rms/data/ssi | grep -v "processed" | tail -n 1) filename=$d export filename... (3 Replies)
Discussion started by: ginowms
3 Replies

LEARN ABOUT REDHAT

gettid

GETTID(2)						     Linux Programmer's Manual							 GETTID(2)

NAME

       gettid - get thread identification

SYNOPSIS

       #include <sys/types.h>

       pid_t gettid(void);

       Note: There is no glibc wrapper for this system call; see NOTES.

DESCRIPTION

       gettid() returns the caller's thread ID (TID).  In a single-threaded process, the thread ID is equal to the process ID (PID, as returned by
       getpid(2)).  In a multithreaded process, all threads have the same PID, but each one has a unique TID.  For further details, see  the  dis-
       cussion of CLONE_THREAD in clone(2).

RETURN VALUE

       On success, returns the thread ID of the calling process.

ERRORS

       This call is always successful.

VERSIONS

       The gettid() system call first appeared on Linux in kernel 2.4.11.

CONFORMING TO

       gettid() is Linux-specific and should not be used in programs that are intended to be portable.

NOTES

       Glibc does not provide a wrapper for this system call; call it using syscall(2).

       The thread ID returned by this call is not the same thing as a POSIX thread ID (i.e., the opaque value returned by pthread_self(3)).

       In  a  new  thread group created by a clone(2) call that does not specify the CLONE_THREAD flag (or, equivalently, a new process created by
       fork(2)), the new process is a thread group leader, and its thread group ID (the value returned by getpid(2)) is the same as its thread	ID
       (the value returned by gettid()).

SEE ALSO

       capget(2),  clone(2), fcntl(2), fork(2), getpid(2), get_robust_list(2), ioprio_set(2), perf_event_open(2), sched_setaffinity(2), sched_set-
       param(2), sched_setscheduler(2), tgkill(2), timer_create(2)

COLOPHON

       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15								 GETTID(2)
All times are GMT -4. The time now is 01:57 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy