102 lines
4.1 KiB
Plaintext
102 lines
4.1 KiB
Plaintext
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{ PASEXEC.INC - interface file for C library routines
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This include file along with the CEXEC.LIB library has been included
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with your Pascal 3.30 to show you how easy it is to call routines
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written in our new C 3.00 release. The CEXEC.LIB contains several
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routines from the C library which we think you will find useful in
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extending the power of your Pascal programs.
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The memory model that Pascal uses is basically medium model (16-bit
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data pointers) with some extensions for large model addressing
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(32-bit data pointers). The CEXEC.LIB routines are from the large
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model C library. This means that you should be careful interfacing
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to these routines. You should use ADS or VARS instead of ADR or VAR
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so that 32-bit addressed get constructed.
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The new Microsoft FORTRAN 3.30, PASCAL 3.30, and C 3.00 releases
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have been designed so that libraries or subprograms can be written
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in any one of these languages and used in any other.
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Try compiling and running the demonstration program DEMOEXEC.PAS
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to see some actual examples.
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}
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{ C function
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int system(string)
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char *string;
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The system() function passes the given C string (00hex terminated)
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to the DOS command interpreter (COMMAND.COM), which interprets and
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executes the string as an MS-DOS command. This allows MS-DOS commands
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(i.e., DIR or DEL), batch files, and programs to be executed.
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Example usage in Pascal
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i := system(ads('dir *.for'*chr(0)));
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The interface to system is given below. The [c] attribute is given
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after the function return type. The [varying] attribute says the
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function has an undetermined number of parameters; in this case, 1.
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}
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function system : integer [c,varying]; extern;
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{ C function
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int spawnlp(mode,path,arg0,arg1,...,argn)
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int mode; /* spawn mode */
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char *path; /* pathname of program to execute */
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char *arg0; /* should be the same as path */
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char *arg1,...,*argn; /* command line arguments */
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/* argn must be NULL */
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The spawnlp creates and executes a new child process. There must be
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enough memory to load and execute the child process. The mode
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argument determines which form of spawnlp is executed as follows:
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Value Action
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0 Suspend parent program and execute the child program.
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When the child program terminates, the parent program
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resumes execution. The return value from spawnlp is -1
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if an error has occured or if the child process has
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run, the return value is the child processes return
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code.
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2 Overlay parent program with the child program. The
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child program is now the running process and the
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parent process is terminated. spawnlp only returns
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a value if there has been a recoverable error. Some
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errors can not be recovered from and execution will
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terminate by safely returning to DOS. This might
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happen if there is not enough memory to run the new
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process.
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The path argument specifies the file to be executed as the child
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process. The path can specify a full path name (from the root
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directory \), a partial path name (from the current working directory),
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or just a file name. If the path argument does not have a filename
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extension or end with a period (.), the spawnlp call first appends
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the extension ".COM" and searches for the file; if unsuccessful, the
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extension ".EXE" is tried. The spawnlp routine will also search for
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the file in any of the directories specified in the PATH environment
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variable (using the same procedure as above).
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Example usage in Pascal
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var NULL : integer4;
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value NULL := 0;
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...
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i := spawnlp(0, ads('exemod'*chr(0)), ads('exemod'*chr(0)),
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ads('demoexec.exe'*chr(0)), NULL);
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The C spawnlp function is expecting the addresses of the strings
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(not the actual characters), so we use the ADS() function to pass
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the address of the strings. The last parameter to the spawnlp
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routine must be a C NULL pointer which is a 32-bit integer 0, so
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we use an INTEGER4 variable NULL set to 0 as the last parameter.
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}
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function spawnlp : integer [c,varying]; extern;
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