unsigned char *map_file(char *filename, uint64_t *len) {
uint64_t fd = open64(filename, O_RDONLY);
struct stat64 st;
fstat64(fd, &st)
unsigned char *map;
map = (unsigned char *)mmap64(0, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
大文件的 st.st_size 最终为 4294967295(我正在针对 8.7gb 文件进行测试)并导致段错误(47%)。机器是 64 位的,操作系统 (ubuntu) 是 64 位的。我做错了什么?
最佳答案
您可能需要定义其中一个宏。
http://www.kernel.org/doc/man-pages/online/pages/man7/feature_test_macros.7.html
_LARGEFILE64_SOURCE
Expose definitions for the alternative API specified by the LFS (Large
File Summit) as a "transitional extension" to the Single UNIX
Specification. (See http://opengroup.org/platform/lfs.html.) The
alternative API consists of a set of new objects (i.e., functions and
types) whose names are suffixed with "64" (e.g., off64_t versus off_t,
lseek64() versus lseek(), etc.). New programs should not employ this
interface; instead _FILE_OFFSET_BITS=64 should be employed.
_FILE_OFFSET_BITS
Defining this macro with the value 64 automatically converts references
to 32-bit functions and data types related to file I/O and file system
operations into references to their 64-bit counterparts. This is
useful for performing I/O on large files (> 2 Gigabytes) on 32-bit
systems. (Defining this macro permits correctly written programs to
use large files with only a recompilation being required.) 64-bit
systems naturally permit file sizes greater than 2 Gigabytes, and on
those systems this macro has no effect.
关于c++ - stat64 在 64 位 ubuntu 上返回 32 位 st_size,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/5072128/