由于title字段包含逗号时要使用引号，我建议您检查一下是否使用了"，如果是，请在第一项中使用该分隔符。

char *field;
if(buff[0] == '"') {
    field = strtok(buff, "\"");
}
else {
    field = strtok(buff, ",");
}

第一个命令将逗号作为下一个字段的第一个字符，但下一个strtok将过滤掉它，因为它不允许“空”字段。

函数strtok不适合您的需要，因为它将引号视为与其他字符一样的字符。因此，当strtok看到逗号时，它不会关心逗号是否在引号内。
此外，正如其他人在评论部分指出的，strtok的另一个问题是它跳过空字段。
因此，我不建议使用strtok来完成您想要的任务。
为了解决你的问题，我建议你自己写一个函数，它的功能和strtok和strsep非常相似，但是如果第一个非whitespace字符是引号，它会把下一个引号当作分隔符，而不是下一个逗号。在下面的代码中，我把这个函数命名为my_strsep。
以下是一个示例：

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

#define NUM_LINES 2

//this function is equivalent to the POSIX function "strsep", except
//that it always uses "," as a delimiter, unless the first
//non-whitespace character is a quotation mark, in which case it //skips the quotation mark and uses the next quotation mark as a
//delimiter, also consuming the next comma
char *my_strsep( char **restrict stringp )
{
    char *p = *stringp;
    char *start;
    char delimiter = ',';

    //do nothing if *stringp is 
    if ( *stringp == NULL )
        return NULL;

    //skip all whitespace characters
    while ( isspace( (unsigned char)*p ) )
        p++;

    //remember start of field
    start = p;

    //determine whether this field uses quotation marks
    if ( *p == '"' )
    {
        //set delimiter to quotation mark instead of comma
        delimiter = '\"';

        //skip the first quotation mark
        p++;
    }

    //remember the start of the string
    start = p;

    while ( *p != delimiter )
    {
        if ( *p == '\0' )
        {
            if ( delimiter == '\"' )
            {
                fprintf( stderr,
                    "Warning: Encountered end of string before the "
                    "second quotation mark!\n"
                );
            }

            //pass information back to calling function
            *stringp = NULL;
            return start;
        }

        p++;
    }

    //overwrite the delimiter with a null character
    *p = '\0';

    //go past the delimiter
    p++;

    //skip the comma too, if quotation marks are being used
    if ( delimiter == '\"' )
    {
        //skip all whitespace characters
        while ( isspace( (unsigned char)*p ) )
            p++;

        //skip the comma
        if ( *p == ',' )
            p++;
    }

    //pass information back to calling function
    *stringp = p;
    return start;
}

int main( void )
{
    char lines[NUM_LINES][200] = {
        "\"The Chronicles of Narnia: The Lion, The Witch and The Wardrobe\",PlayStation 2,8,2005",
        "The Chronicles of Narnia: Prince Caspian,Wireless,5,2008"
    };

    for ( int i = 0; i < NUM_LINES; i++ )
    {
        char *p, *q;

        printf( "Processing line #%d:\n", i + 1 );

        p = lines[i];

        while ( ( q = my_strsep( &p ) ) != NULL )
        {
            printf( "Found field: %s\n", q );
        }

        printf( "\n" );
    }
}

此程序具有以下输出：

Processing line #1:
Found field: The Chronicles of Narnia: The Lion, The Witch and The Wardrobe
Found field: PlayStation 2
Found field: 8
Found field: 2005

Processing line #2:
Found field: The Chronicles of Narnia: Prince Caspian
Found field: Wireless
Found field: 5
Found field: 2008

如您所见，函数my_strsep可以处理带引号和不带引号的字段。