[英]Pass a value greater than maximum value of long type to fseek in C
I need to pass some values to the fseek()
method in C which are greater than the maximum value of the signed long type (2147483647). 我需要将一些值传递给C中的fseek()
方法,该方法大于signed long类型的最大值(2147483647)。 But if I do like below the value of the result is -1 which is not success. 但如果我喜欢下面结果的值是-1,这是不成功的。 Is there anyway that I can do this? 无论如何我能做到这一点吗?
//fp is the pointer to fopen method
unsigned long long index=2147483648;
int status = fseek(fp, index, SEEK_SET);
Since you tagged this with "Objective-C", I'm assuming you are also thinking about Macintosh. 既然你用“Objective-C”标记了这个,我假设你也在考虑使用Macintosh。
Check out fseeko
(which takes a 64bit number). 查看fseeko
(需要64位数字)。
You need to use the 64-bit version of fseek()
: 您需要使用64位版本的fseek()
:
_fseeki64()
Windows: _fseeki64()
fseeko()
with #define _FILE_OFFSET_BITS 64
or -D_FILE_OFFSET_BITS=64
Linux: fseeko()
#define _FILE_OFFSET_BITS 64
或-D_FILE_OFFSET_BITS=64
And for lseek()
: 对于lseek()
:
_lseeki64()
Windows: _lseeki64()
lseek()
with #define _FILE_OFFSET_BITS 64
or -D_FILE_OFFSET_BITS=64
Linux: lseek()
使用#define _FILE_OFFSET_BITS 64
或-D_FILE_OFFSET_BITS=64
There's also lseek64()
, but as mentioned by @R.. (see comments), it should not be used. 还有lseek64()
,但正如@R所提到的那样(见注释),不应该使用它。
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