waitpid return value
If status is not NULL, wait() and waitpid() store status infor- mation in the int to which it points. This integer can be inspected with the following macros (which take the integer itself as an argument, not a pointer to it, as is done in wait() and wai, Per @Geoff_Montee's advice, there was a bug in my redirect of STDERR , but this was not responsible for the problem as execvp does not store the return value in STDERR or even STDOUT , but rather in the kernel object associated with the parent proces
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 waitpid return value 相關參考資料
c - waitpid() return value 0 along with errno EINTR - Stack Overflow
When called with WNOHANG , waitpid() returns 0 when there are no more children left to reap. Your SIGCHLD handler gets called when a child process exits, so you know there'll always be at least o... https://stackoverflow.com c - What does the second parameter of waitpid() mean? - Stack Overflow
If status is not NULL, wait() and waitpid() store status infor- mation in the int to which it points. This integer can be inspected with the following macros (which take the integer itself as an argu... https://stackoverflow.com c++ - waitpidwexitstatus returning 0 instead of correct return ...
Per @Geoff_Montee's advice, there was a bug in my redirect of STDERR , but this was not responsible for the problem as execvp does not store the return value in STDERR or even STDOUT , but rather... https://stackoverflow.com How to make sure that `waitpid(-1, &stat, WNOHANG)` collect all ...
The loop is because while you are in the handler itself a 2nd or 3rd child could have changed or terminated sending SIGCHLDs that would not be queued. Thus the loop actually prevents you from missing... https://stackoverflow.com signals - Return value of waitpid() in linux - Stack Overflow
If wait() or waitpid() returns because the status of a child process is available, these functions shall return a value equal to the process ID of the child process for which status is reported. (...... https://stackoverflow.com wait(2) - Linux manual page - man7.org
#include <sys/types.h> #include <sys/wait.h> pid_t wait(int *wstatus); pid_t waitpid(pid_t pid, int *wstatus, int options); int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int optio... http://man7.org waitpid() -- wait for process termination - MKS Toolkit
If waitpid() was invoked with WNOHANG set in options, and there are children specified by pid for which status is not available, waitpid() returns 0. If WNOHANG was not set, waitpid() returns the proc... https://www.mkssoftware.com waitpid() — Wait for a specific child process to end - IBM
If pid is -1, waitpid() waits for any child process to end. If pid is less than -1, waitpid() waits for the termination of any child whose process group ID is equal to the absolute value of pid. int *... https://www.ibm.com waitpid(2): wait for process to change state - Linux man page
Return Value. wait(): on success, returns the process ID of the terminated child; on error, -1 is returned. waitpid(): on success, returns the process ID of the child whose state has changed; if WNOHA... https://linux.die.net waitpid(3) - Linux man page
If wait() or waitpid() return because the status of a child process is available, these functions shall return a value equal to the process ID of the child process. In this case, if the value of the a... https://linux.die.net |