So you want to write a C program for the IBM PC before the first C compiler for the PC is released. How do you go about it?

There are three options I can see:

1. Write your own C compiler
2. Use a cross compiler for 8086 on some other platform
3. Wait for a C compiler to become available
4. Don't use C

No four options. Amongst our many options are fear surprise and a fanatical devotion to the Pope.

I'd be pretty confident that all of the software houses that were in that position would have gone with option 4. The reason for this is that the premise of your question is faulty: professional software developers don't have dogmatic views about which language to use, they look at the target platform and then pick (what they think is) the best language that is available. In my 30 years as a professional software developer, I have never had the luxury of a free choice of what language to use on any project. On a professional level, my favourite language is whichever one gets the job done on the target platform. For my personal projects, it's Swift all the way.

Another point to remember is that, in 1981, C did not have the ubiquity in the world of personal computers that it later gained. Everybody wrote in BASIC or assembler. The deficiencies of BASIC were recognised but the answer was not obviously "replace it with C". Several languages were mooted as a replacement including IIRC Pascal, COMAL and even Fortran but the first time I even heard of C was when I went to University in 1984 and was exposed for the first time to Unix. There was a significant group of people who thought "why would you use anything but assembler?"

The software house developing an application for the IBM PC in 1981 would have had no hesitation in breaking out the 8086 assembler and just getting on with it.

So you want to write a C program for the IBM PC before the first C compiler for the PC is released. How do you go about it?

There are three options I can see:

1. Write your own C compiler
2. Use a cross compiler for 8086 on some other platform
3. Wait for a C compiler to become available
4. Don't use C

No four options. Amongst our many options are fear, surprise and a fanatical devotion to the Pope.

I'd be pretty confident that all of the software houses that were in that position would have gone with option 4. The reason for this is that the premise of your question is faulty: professional software developers don't have dogmatic views about which language to use, they look at the target platform and then pick (what they think is) the best language that is available. In my 30 years as a professional software developer, I have never had the luxury of a free choice of what language to use on any project. On a professional level, my favourite language is whichever one gets the job done on the target platform. For my personal projects, it's Swift all the way.

Another point to remember is that, in 1981, C did not have the ubiquity in the world of personal computers that it later gained. Everybody wrote in BASIC or assembler. The deficiencies of BASIC were recognised but the answer was not obviously "replace it with C". Several languages were mooted as a replacement including IIRC Pascal, COMAL and even Fortran but the first time I even heard of C was when I went to University in 1984 and was exposed for the first time to Unix. There was a significant group of people who thought "why would you use anything but assembler?"

The software house developing an application for the IBM PC in 1981 would have had no hesitation in breaking out the 8086 assembler and just getting on with it.