如何获取读取的字节数
当我像这样从stdin读取时：
size_t bufSize = 1024;
unsigned char inputBuffer[bufSize];
size_t readNum = 0;
readNum = fread(inputBuffer, sizeof(unsigned char) * bufSize, 1, stdin);
在readNum中存储了对象的数量，这意味着当我从stdin读取1024字节时，readNum的值为1。但是当我从stdin读取时，readNum的值为1。 1024 字节，比 readNum 的值为 0。问题是，当数字小于 1024 时，如何识别从 stdin 读取了多少字节？
when I read from stdin like this:
size_t bufSize = 1024;
unsigned char inputBuffer[bufSize];
size_t readNum = 0;
readNum = fread(inputBuffer, sizeof(unsigned char) * bufSize, 1, stdin);
in the readNum are stored number of object, this mean when I read from stdin 1024 bytes, the readNum has value 1. But when I read from stdin < 1024 bytes, than readNum has value 0. Question is, how can I recognize how many bytes was read from stdin when the number is less then 1024?
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使用 readNum = fread(inputBuffer, sizeof(unsigned char), bufSize, stdin);
您正在尝试读取
bufSize元素，每个元素都有一个大小sizeof( char)- 不是一个大小为bufSize * sizeof(char)的元素 - 因此您的fread调用应该反映这一点。Use
readNum = fread(inputBuffer, sizeof(unsigned char), bufSize, stdin);You're trying to read
bufSizeelements, each with a sizesizeof(char)- not one element with a size ofbufSize * sizeof(char)- so yourfreadcall should reflect that.fread 读取给定大小的块并返回成功读取的块的数量。
如果要返回读取的字节数，请将块大小设置为 1，并将块数设置为要读取的字节数：
fread reads blocks with the given size and returns the number of sucessfully read blocks.
If you want to return the number of bytes read then set the blocksize to 1 and the number of blocks to the number of bytes you want to read: