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dup(2) [sunos man page]

dup(2)								   System Calls 							    dup(2)

NAME
dup - duplicate an open file descriptor SYNOPSIS
#include <unistd.h> int dup(int fildes); DESCRIPTION
The dup() function returns a new file descriptor having the following in common with the original open file descriptor fildes: o same open file (or pipe) o same file pointer (that is, both file descriptors share one file pointer) o same access mode (read, write or read/write). The new file descriptor is set to remain open across exec functions (see fcntl(2)). The file descriptor returned is the lowest one available. The dup(fildes) function call is equivalent to: fcntl(fildes, F_DUPFD, 0) RETURN VALUES
Upon successful completion, a non-negative integer representing the file descriptor is returned. Otherwise, -1 is returned and errno is set to indicate the error. ERRORS
The dup() function will fail if: EBADF The fildes argument is not a valid open file descriptor. EINTR A signal was caught during the execution of the dup() function. EMFILE The process has too many open files (see getrlimit(2)). ENOLINK The fildes argument is on a remote machine and the link to that machine is no longer active. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Async-Signal-Safe | +-----------------------------+-----------------------------+ SEE ALSO
close(2), creat(2), exec(2), fcntl(2), getrlimit(2), open(2), pipe(2), dup2(3C), lockf(3C), attributes(5), standards(5) SunOS 5.10 28 Dec 1996 dup(2)

Check Out this Related Man Page

dup2(3C)						   Standard C Library Functions 						  dup2(3C)

NAME
dup2 - duplicate an open file descriptor SYNOPSIS
#include <unistd.h> int dup2(int fildes, int fildes2); DESCRIPTION
The dup2() function causes the file descriptor fildes2 to refer to the same file as fildes. The fildes argument is a file descriptor refer- ring to an open file, and fildes2 is a non-negative integer less than the current value for the maximum number of open file descriptors allowed the calling process. See getrlimit(2). If fildes2 already refers to an open file, not fildes, it is closed first. If fildes2 refers to fildes, or if fildes is not a valid open file descriptor, fildes2 will not be closed first. The dup2() function is equivalent to fcntl(fildes, F_DUP2FD, fildes2). RETURN VALUES
Upon successful completion a non-negative integer representing the file descriptor is returned. Otherwise, -1 is returned and errno is set to indicate the error. ERRORS
The dup2() function will fail if: EBADF The fildes argument is not a valid open file descriptor. EBADF The files2 argument is negative or is not less than the current resource limit returned by getrlimit(RLIMIT_NOFILE, ...). EINTR A signal was caught during the dup2() call. EMFILE The process has too many open files. See fcntl(2). ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Async-Signal-Safe | +-----------------------------+-----------------------------+ SEE ALSO
close(2), creat(2), exec(2), fcntl(2), getrlimit(2), open(2), pipe(2), lockf(3C), attributes(5), standards(5) SunOS 5.10 19 Dec 2003 dup2(3C)

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