写一个二进制文件？ [英] write a binary file?
问题描述
亲爱的，
我打开一个二进制文件，想把0x00040700写入这个文件。
如何设置写缓冲区？
--------------------------------------------- ------
typedef unsigned char UCHAR;
int iFD = open（szFileName，O_CREAT | O_BINARY | O_TRUNC | O_WRO NLY，S_IREAD | S_IWRITE）;
UCHAR buffer [5]; // ??????????
写（iFD，缓冲区，5）;
------------ ---------------------------------------
谢谢。
问候，
cylin。
Dear all,
I open a binary file and want to write 0x00040700 to this file.
how can I set write buffer?
---------------------------------------------------
typedef unsigned char UCHAR;
int iFD=open(szFileName,O_CREAT|O_BINARY|O_TRUNC|O_WRO NLY,S_IREAD|S_IWRITE);
UCHAR buffer[5]; //???????????
write(iFD,buffer,5);
---------------------------------------------------
Thanks.
Regards,
cylin.
推荐答案
" cylin" < CY *** @ avant.com.tw>写道：
"cylin" <cy***@avant.com.tw> wrote:
我打开一个二进制文件，想写0x00040700到这个文件。
如何设置写缓冲区？
在ISO C中不是这样的。你所拥有的是系统特定的，或者是
POSIX或者不是 - 相当于POSIX-M
I open a binary file and want to write 0x00040700 to this file.
how can I set write buffer?
Not like this, in ISO C. What you''ve got is system-specific, either
POSIX or not-quite-POSIX-M
。
typedef unsigned char UCHAR;
Yeugh。
int iFD = open（szFileName，O_CREAT | O_BINARY | O_TRUNC | O_WRO NLY，S_IREAD | S_IWRITE）;
匈牙利表示法。双倍的。 HN过去常常声明每个人读取你的代码，包括编译器，已经知道：
你的标识符类型。三倍，然后去自信店和
买一些。
UCHAR缓冲[5]; // ???????????
混合声明和可执行语句在C99和C ++中是合法的，
但不在C89中。小心嗤之以鼻。
写（iFD，缓冲区，5）;
.
typedef unsigned char UCHAR;
Yeugh.
int iFD=open(szFileName,O_CREAT|O_BINARY|O_TRUNC|O_WRO NLY,S_IREAD|S_IWRITE);
Hungarian notation. Double yeugh. HN used to declare what everybody
reading your code, including the compiler, already knows: the types of
your identifiers. Triple yeugh, and go to the self-confidence shop and
buy some.
UCHAR buffer[5]; //???????????
Mixing declarations and executable statements is legal in C99 and C++,
but not in C89. Beware the snark.
write(iFD,buffer,5);
不知道如何使用低级别来解决这个问题，不太可能到港口
功能。在_real_ C中，你会做这样的事情：
#include< stdio.h>
unsigned char buf [5 ];
FILE * outfile;
if（！（outfile = fopen（filename，" wb"））{
puts（这是你处理文件打开错误的地方。）;
} else {
if（fwrite（buf，sizeof） * buf，sizeof buf / sizeof * buf，outfile）！=
sizeof buf / sizeof * buf）{
puts（在此处理写入错误。 ）;
}
/ *或者，因为你知道buf是一个unsigned char数组而且
因此sizeof * buf必须是1：
fwrite（缓冲区，1，sizeof buf，outfile）;
* /
fclose（outfile）;
/ *对于关键应用程序，你甚至应该检查fclose（）的返回值
，但我很少这样做。* /
}
Issa dat si''ple。
Richard
No idea how to solve this using your low-level, unlikely-to-port
functions. In _real_ C, you''d do something like this:
#include <stdio.h>
unsigned char buf[5];
FILE *outfile;
if (!(outfile=fopen(filename, "wb")) {
puts("This is the place where you''d handle a file open error.");
} else {
if (fwrite(buf, sizeof *buf, sizeof buf/sizeof *buf, outfile) !=
sizeof buf/sizeof *buf) {
puts("Handle a write error here.");
}
/* Or, since you know that buf is an unsigned char array and
therefore sizeof *buf must be 1:
fwrite(buffer, 1, sizeof buf, outfile);
*/
fclose(outfile);
/* For critical applications, you should even check the return value
of fclose(), but I rarely do this. */
}
Issa dat si''ple.
Richard
" cylin"< cy ** * @ AV ant.com.tw>写道：
"cylin" <cy***@avant.com.tw> wrote:
我打开一个二进制文件，想把0x00040700写入这个文件。
如何设置写缓冲区？
你想要
[1]按照你上面给出的顺序写入字节（便携式
结果），或者
[2]写一个unsigned long值给文件（非便携式
结果）？
-------- -------------------------------------------
typedef unsigned char UCHAR;
int iFD = open（szFileName，O_CREAT | O_BINARY | O_TRUNC | O_WRO NLY，S_IREAD | S_IWRITE）;
UCHAR buffer [5]; // ??????????
写（iFD，缓冲区，5）;
-------------------- -------------------------------
I open a binary file and want to write 0x00040700 to this file.
how can I set write buffer?
Do you want to
[1] write bytes in exactly the order you gave above (portable
result), or
[2] write an unsigned long value to the file (non-portable
result)?
---------------------------------------------------
typedef unsigned char UCHAR;
int iFD=open(szFileName,O_CREAT|O_BINARY|O_TRUNC|O_WRO NLY,S_IREAD|S_IWRITE);
UCHAR buffer[5]; //???????????
write(iFD,buffer,5);
---------------------------------------------------
既不开放也不开放写是标准的C函数。
你想要的是：
#include< stdio.h>
＃ include< stdlib.h>
int main（void）
{
unsigned char buf [] = {0x00， 0x04,0x07,0x00};
unsigned long ul = 0x00040700UL;
FILE * fp;
if（（fp = fopen（" foo"，" wb"））！= NULL）
{
fwrite（buf，sizeof buf，1，fp）; / * [1] * /
fwrite（& ul，sizeof ul，1，fp）; / * [2] * /
fclose（fp）;
返回EXIT_SUCCESS;
}
返回EXIT_FAILURE ;
}
HTH
问候
-
Irrwahn Grausewitz（ir*******@freenet.de）
欢迎来到clc： http://www.ungerhu.com/jxh/clc.welcome.txt
clc faq-list： http://www.faqs.org/faqs/C-faq/faq/
clc OT指南： http ：//benpfaff.org/writings/clc/off-topic.html
Neither open nor write are standard C functions.
What you want is something like:
#include <stdio.h>
#include <stdlib.h>
int main( void )
{
unsigned char buf[] = { 0x00, 0x04, 0x07, 0x00 };
unsigned long ul = 0x00040700UL;
FILE *fp;
if ( ( fp = fopen( "foo", "wb" ) ) != NULL )
{
fwrite( buf, sizeof buf, 1, fp ); /* [1] */
fwrite( &ul, sizeof ul, 1, fp ); /* [2] */
fclose( fp );
return EXIT_SUCCESS;
}
return EXIT_FAILURE;
}
HTH
Regards
--
Irrwahn Grausewitz (ir*******@freenet.de)
welcome to clc: http://www.ungerhu.com/jxh/clc.welcome.txt
clc faq-list : http://www.faqs.org/faqs/C-faq/faq/
clc OT guide : http://benpfaff.org/writings/clc/off-topic.html
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