lseek的返回值
时间：2010-07-19
来源：互联网
APUE中说有些设备允许lseek的返回值偏移量为负数，那lseek(fd, -1, SEEK_SET)返回的－1表示偏移量还是表示出错阿？
下面摘自APUE Section3.6
Normally, a file's current offset must be a non-negative integer. It is possible, however, that certain devices could allow negative offsets. But for regular files, the offset must be non-negative. Because negative offsets are possible, we should be careful to compare the return value from lseek as being equal to or not equal to 1 and not test if it's less than 0.
下面摘自APUE Section3.6
Normally, a file's current offset must be a non-negative integer. It is possible, however, that certain devices could allow negative offsets. But for regular files, the offset must be non-negative. Because negative offsets are possible, we should be careful to compare the return value from lseek as being equal to or not equal to 1 and not test if it's less than 0.
作者: nnuyjh569 发布时间: 2010-07-19
man lseek
QUOTE:
RETURN VALUE
Upon successful completion, lseek() returns the resulting offset loca‐
tion as measured in bytes from the beginning of the file. Otherwise, a
value of (off_t) -1 is returned and errno is set to indicate the error.
Upon successful completion, lseek() returns the resulting offset loca‐
tion as measured in bytes from the beginning of the file. Otherwise, a
value of (off_t) -1 is returned and errno is set to indicate the error.
作者: churchmice 发布时间: 2010-07-19
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