MLTestUTF8Head()

MLTestUTF8Head 已经被 WSTestUTF8Head 所取代.

int MLTestUTF8Head(MLINK l, const unsigned char *h, int v, int *n)

tests that the next expression to be read from l is an expression with the head h and a UTF-8 encoded name of length v, and stores the number of arguments of the expression in n.

更多信息和选项更多信息
  • MLTestUTF8Head() fails if the current expression on the link is not a function with a symbol as a head, or if the name of the symbol does not match h.
  • MLTestUTF8Head() returns 0 in the event of an error, and a nonzero value if the function succeeds.
  • Use MLError() to retrieve the error code if MLTestUTF8Head() fails.
  • MLTestUTF8Head() will reset the stream pointer to the expression on the link just prior to calling MLTestUTF8Head() if the function fails. This operation behaves as if the programmer called WLCreateMark(l); MLTestUTF8Head(); MLSeekToMark().
  • MLTestUTF8Head() is declared in the MathLink header file mathlink.h.
  • 范例

    基本范例  (1)

    #include "mathlink.h"

    /* A function for testing whether the next expression on the link is a ReturnPacket[] */

    void f(MLINK l)
    {
        const unsigned char packet[12];
        int arguments;

        packet[0] = 'R';
        packet[1] = 'e';
        packet[2] = 't';
        packet[3] = 'u';
        packet[4] = 'r';
        packet[5] = 'n';
        packet[6] = 'P';
        packet[7] = 'a';
        packet[8] = 'c';
        packet[9] = 'k';
        packet[10] = 'e';
        packet[11] = 't';

        if(! MLTestUTF8Head(l, (const unsigned short *)packet, 12,
            &arguments))
        { /* read the contents of the ReturnPacket[] */ }
        else
        { /* the head of the incoming expression is not ReturnPacket */ }
    }

    参见

      {}

    2014年引入
    (10.0)