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POSIX_FALLOCATE(3) Linux Programmer's Manual POSIX_FALLOCATE(3) NAME posix_fallocate - allocate file space SYNOPSIS #define _XOPEN_SOURCE 600 #include <stdlib.h> int posix_fallocate(int fd, off_t offset, off_t len); DESCRIPTION The function posix_fallocate() ensures that disk space is allocated for the file referred to by the descriptor fd for the bytes in the range starting at offset and continuing for len bytes. After a successful call to posix_fallocate(), subsequent writes to bytes in the specified range are guaranteed not to fail because of lack of disk space. If the size of the file is less than offset+len, then the file is increased to this size; otherwise the file size is left unchanged. RETURN VALUE posix_fallocate() returns zero on success, or an error number on fail- ure. Note that errno is not set. ERRORS EBADF fd is not a valid file descriptor, or is not opened for writing. EFBIG offset+len exceeds the maximum file size. EINVAL offset or len was less than 0. ENODEV fd does not refer to a regular file. ENOSPC There is not enough space left on the device containing the file referred to by fd. ESPIPE fd refers to a pipe of file descriptor. VERSIONS posix_fallocate() is available since glibc 2.1.94. CONFORMING TO POSIX.1-2001. SEE ALSO lseek(2), posix_fadvise(2), feature_test_macros(7) GNU 2006-03-01 POSIX_FALLOCATE(3)