<html><head><base href="x-msg://12/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 14 Feb 2014, at 20:28, Fred van Stappen wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div class="hmmessage" style="font-size: 12pt; font-family: Calibri; "><div dir="ltr">>What I have been wondering for some time now (perhaps you wrote it in a<br>>mail and I missed it): do you use the same memory manager in the library<br>>and in your test program?<br><br>Oops, indeed i forget that point...<br>The test now are with cmem only in program, not in library.<br><br>I will test with cmem into library too...<br></div></div></span></blockquote><div><br></div><div>That that is issue number 1: if your program wants to free something that your library allocated, both operations need to be done by the same memory manager.</div><br><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div class="hmmessage" style="font-size: 12pt; font-family: Calibri; "><div dir="ltr"><div><div><div><br></div>>The example here might be extremely over-simplified, but replace<br>> `a: Integer` with `mystring: String` and we're roughly at your example.<br><br>Hum, absolutely, it is the same example...<span class="Apple-converted-space"> </span><br>So, how must i do to use PChar ?<br></div></div></div></div></span></blockquote><div><br></div></div>The way I use to pass strings from C/C++ libraries is to allocate a buffer, copy the contents of the string into the buffer and return the pointer to that buffer. The same method can be used here. Also don't forget to provide a second function to free these buffers (in this way your library can have a different memory manager than your application).<div><br></div><div>So you might try something along the lines of:</div><div><br></div><div>Function ConvertToPChar(str: String): PChar;</div><div>Begin</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>Result:= Getmem(Length(str) + 1);<span class="Apple-tab-span" style="white-space:pre"> </span>// Allocating the buffer somewhere on the heap</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>If Length(str) > 0 Then</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>Move(str[1], Result[0], Length(str));<span class="Apple-tab-span" style="white-space:pre"> </span>// The content</div><div><span class="Apple-tab-span" style="white-space:pre"> </span></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>Result[l]Length(str)]:= #0;<span class="Apple-tab-span" style="white-space:pre"> </span>// The null termination</div><div>End;</div><div><br></div><div>..., where I decided to return `standard` null-terminated strings, since your library is meant to be `universal`.</div><div><br></div><div>Next, the procedure to free buffers using the memory manager of the library:</div><div><br></div><div>Procedure FreeBuffer(Buffer: Pointer);</div><div>Begin</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>FreeMem(Buffer);</div><div>End;</div><div><br></div><div>That's it for the library part. In your program part, don't forget to free these buffers once they are no longer needed.</div><div><br></div><div>Also note that this is a good approach with respect to `universiality`, but if you need to pass a lot of strings to and fro you would be better off with a more pascalish version. The thing that comes to mind here is providing a function in your library that replaces the current memory manager with the one passed to it as an argument. This would allow you to simply return a string.</div><div><div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div style="font-size: medium; color: rgb(0, 0, 0); font-style: normal; ">--</div><div style="font-size: medium; color: rgb(0, 0, 0); font-style: normal; ">Ewald</div></div></span></div></span></div></span></div></span></span>
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