fread()
Reads a number of bytes from a file to a blob variable.
Synopsis
int fread(file f, blob &b[, int numBytes]);
Parameters
| Parameters | Meaning |
|---|---|
| f | File to be read |
| b | blob variable |
| numBytes | Number of bytes to be read. This argument is optional, if it is not given all bytes until EOF are read. |
Return value
In the event of errors, the function returns -1 or EOF otherwise, the number of read characters.
Description
Reads a number of bytes from a file to a blob variable.
If you set numBytes == 0 (or e.g. reading an empty
file) the result will be an empty blob.
Example
Writes 4 bytes and reads 2 bytes to/from a file.
main()
{
blob target, rtarget;
int len, pos;
string s;
anytype value;
bool bigendian;
s = "FFAB003AFF";
target = s;
DebugN(target);
len = 1;
value = 5;
bigendian = TRUE;
DebugN("Blob AppendValue: " + blobAppendValue(target, value, len, bigendian)); //blob length is 6 = FF AB 0 3A FF 5
DebugN(target); //ff ab 0 3a ff 5
int fr, fw, numW, fcl, err, numR;
file wf;
wf = fopen("D:\\BFile.txt", "w");
numR = 2;
numW = 4;
err = ferror(wf);
fw = fwrite(wf, target, numW);
DebugN("Number of bytes that could be written:", fw);
//Output: ["Number of bytes that could be written:"][4]
fr = fread(wf, rtarget, numR);
DebugN("Number of bytes that could be read:", fr);
//Output: ["Number of bytes that could be read:"][2]
fcl = fclose(wf);
}Assignment
File functions
Availability
CTRL
