National Instruments 320682C

Chapter 2 Formatting and I/O Library

case 2:

Fmt (buf, "%s<TRIANGLE;");

break;

}

switch (signal_output) {

case 0:

Fmt (buf, "%s[a]<OUTPUT OFF;");

break;

case 1:

Fmt (buf, "%s[a]<OUTPUT ON;");

break;

}

nbytes = StringLength (buf);

Remarks

This example shows how to append characters to a string without writing over the existing

contents of the string. The first switch construct writes one of three strings into buf. The

second switch construct appends one of two strings to the string already in buf. After the

call, buf contains "SQUARE;OUTPUT OFF;". Notice that the a modifier applies to the

target specifier.

StringLength returns the number of bytes in the resulting string. In this case,

StringLength is used instead of NumFmtdBytes, because NumFmtdBytes would return

only the number of bytes appended.

Creating an Array of File Names

char *fname_array[4];

int i;

fname_array[0] = " "; /* 13 spaces */

fname_array[1] = " "; /* 13 spaces */

fname_array[2] = " "; /* 13 spaces */

fname_array[3] = " "; /* 13 spaces */

for (i=0; i < 4; i++)

Fmt (fname_array[i], "%s<FILE%i[w4p0].DAT", i);

Remarks

To allocate the space for each filename in the array, a separate constant string must be assigned

to each array element. Then Fmt is used to format each file name. The resulting file names are

FILE0000.DAT, FILE0001.DAT, FILE0002.DAT, and FILE0003.DAT.